Digester will turn methane into electricity

POTSDAM  St. Lawrence County dairy farmer Jon R. Greenwood is ready to turn on the switch on an anaerobic digester that will take the methane produced by manure from his cows and turn it into electricity.

Theres other farms looking at it, Mr. Greenwood said. Were the only ones doing it right now. You need cow numbers to make it viable. I would say 700 at least.

In 2008, Greenwood Dairy Farm on Route 310  which Mr. Greenwood operates with his wife, Linda R.  was awarded a $433,564 grant from the U.S. Department of Agriculture and a commitment from New York State Energy Research and Development Authority for $700,000 paid out over three years based on successful operation of the digester.

However, Mr. Greenwood shelved the project out of uncertainty that the positives outweighed the uncertainties.

Earlier this year, NYSERDA increased the amount of funding available and changed the terms, providing a total incentive package of $2 million, including the payout of $700,000 spread out over 10 years based on the kilowatt-hours of electricity produced.

If it quits running, you dont get that money, Mr. Greenwood said.

The $433,564 federal grant remains available if the project is up and running this fall.

NYSERDA also made the deal more attractive by paying more of the upfront costs of construction, said Mr. Greenwood, president of the St. Lawrence County Farm Bureau and a former county legislator.

The project will end up costing more than $3 million, including Greenwood Dairy paying for an electrical system upgrade from single-phase to three-phase power, which can provide commercial applications with more efficiency.

Were already maxing out the single-phase line. Thats part of my equation whether this pays, Mr. Greenwood said. If anyone already has three-phase electricity, their cost would be substantially less.

Manure from Greenwoods 1,300 mature cows and 1,200 young stock will be piped to a 1.3 million-gallon tank that is 18 feet deep and 120 feet across where methane gas will be produced. Mixers within the tank will keep the manure circulating. The tank will have two covers with a sandwich layer of insulation.

The gas produced will be piped to a separate building where a generator will produce electricity from the methane. Water from the cooling engine will be used to heat the manure in the tank to the right temperature to produce the gas.

Well use what we need of the electricity and the extra will be sold to National Grid, Mr. Greenwood said.

Project designer and contractor is RCM Digesters, Berkeley, Ca.

Solids left from the manure will be used for bedding while the liquid will be used for fertilizer, minus much of the odor.

Those are benefits, Mr. Greenwood said.

The Greenwood project aligns with Gov. Andrew M. Cuomos call to increase the states amount of energy produced by renewable resources, NYSERDA Director of Communications Kate T. Muller said in an email.

Additionally, this technology supports the goals of the governors yogurt summit as it assists farmers more easily manage the waste produced by cows and it saves money on energy costs by turning that waste into a renewable source of energy, she said.

NYSERDA is helping a large business reduce its capital expenses while increasing the amount of energy created through a renewable resource, which cuts the states use of fossil fuels and emission of greenhouse gases and eases strain on the electric grid, Ms. Muller said.

As energy costs go up, alternatives become more attractive. Without the grants, it would not be economically feasible, Mr. Greenwood said. As technology improves, the cost goes down.

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